If you have a look at the Appearance section of Enel's wiki page, you can see that (emphasis mine)
Enel is a tall, muscular man who has white/blond hair which was, in ancient South American civilizations, considered godly..
His nose has many lines running horizontally across it. His ear lobes are extremely long, ending up to his torso. He also holds four large Tomoe drums attached via a large ring to his back, instead of the regular Skypiean/Birkan wings, which gives him an appearance similar to a Raijin, a similarity made even more prominent when using his "200,000,000 Volt Amaru" transformation.
So they are basically just external features of his attire and not really something which he has transplanted to his body.